The introduction of High Speed Trains (HSTs) on the East Coast Mainline (ECML) in the late 1970s marked the beginning of the end for the Class 55 Deltic locomotives.

Two locomotives were withdrawn in 1980. From here onwards class members were slowly taken out of service during 1981 as they failed or became too expensive to repair, their parts robbed to keep other members running.

The majority of the Class 55 fleet met their demise at the scrap yard. Some however, thanks to numerous dedicated enthusiasts, have been preserved or are currently being restored for future generations at the many private railways across the country.